Feed-valve device



' Ap12'3,1929. w. MEAN' 1,709,899

FEED VALVE DEVICE Filed Nov. 13, 1925 mmllllw V ATTORNEY Patented Apr. 23, 1929.

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i WILLIAM ii. DEAN, vor wrtiilpiissune, rnnivsvtvauia, Assenonmoxfrnn vvnsmiive.; vHouse AIRBRAKE coil/freier, or'wiiiivinnniiie, PENNSYLVANIA, 'A CORORATION 0F PENNSYLVANIA.

FEED-VALVE DEVICE.

iippiietion. rues November is, 1925.* sei-iai N oqeasss.

This lini'ention relates to pressure regulatg ing valve devices, and' more particularly to a feed valve device for"maintainingtlie pressure inthe brake pipe of a' fluidpressure brakesystein at a predetermined degree.

The standard feed valve device at present employed inv connection withl fluid pressure brake systems, comprises a fluid vpressure 'supply portion having a piston adapted to be operated upon a reduction iu fluid pressure to actuate a supply valve, and a regulating portion which operates to effect a reduction in fluid pressure on said supply piston when the pressure in the brake pipe falls below a predetermined degree. f

In order to improve the operation of the Vfeed valve device', it has heretofore been proposed to provide means for accelerating` the action of the regulating portion by introducingV a.V Venturi tube, which is so disposed that the flow of fluid from the supply portion to the brake pipe causes a suction effect on the regulating portion and thereby accelerates the action of said regulating portion by reducing the pressure thereon to a degree less than the pressure existing in the brake pipe.

l/Vhen a Venturi tube is employed in the feed valve device for the above purpose, it has been found that the accelerating action is apt to be excessive and is liable to cause an overcharging of the'bra'ke pipe.

The principal object of my invention is to provide a feed valve device having a Venturi tube for the above purpose, and means for preventing an excessive accelerating action of the Venturi tube.

In the accompanying drawing, the single figure is a central sectional view of a feed.

valve device embodying my invention.

As shown in the drawing, the feed valve device may comprise a casing 1, containing a fluid pressure supply portion and a regulating portion. The regulating portion coinprises a diaphragm 2 subject on one side to the pressure of an adjustable spring 3 and on the other side to the pressure of the brake pipe 4 or other outlet pressure. lSaid diaphragm is'adapted to operate a valve 5 for venting fluid from the fluid pressure supply' portion.

The supply portion comprises a piston- 6, contained in piston chamber 7, and a slide valve 8, contained in valve chamber 9, and

adapted to be operated by piston 6.

rlhe supply valveSis provided with two supply ports 10 and 11 adapted' to register' respectively with vports 12 andl, when the y slide valve is moved outwardly by thepiston l (i, and interposedii the v,passage connecting thev ports 12 and 13 with the brake pipe 4 is 'a Venturi tube device 14 vwhich provides communication from the" brake pipe 4; through passage 15 to the-diaphragm 2 of the regulating port-ion and which operates according to .the rate of flow of fluid from the supply valve 8 to the brake pipe to cause a suction effect, so as tol reduce the vpressure of fluid acting'on the diaphragm 2.

'The port l11 is positioned to partly register with' port slightly beforeA the` port "10 commencesto registerv with port 12, land aecordingv to iny invention, two springs are provided to oppose the outward movement of piston G. AThe spring 16 opposes movement from vthe initial inner position, while spring 17 is adapted to oppose movement of the pisvalve 5 is in its seated position, the fluid pressures on opposite sides of piston 6 are per- `mitted to equalize, and spring 16 then maintains the piston 6 in its inner position, as shown in the drawing.

If the pressure in the brake pipe 4 should fallbelow the pressure at which the sprinO' 3 of the regulating portion may be adjuste the reduced pressure on diaphragm 2 permits tlie spring 3 to 'move the diaphragm so as to effect the opening of the valve 5. Fluid under pressure is then vented from piston chamber 7 to passage l5 and piston 6 is moved outwardly by the higher pressure in valve chamber 9, compressing the spring 16.

The slide valve 8 moves out until the port 11 commences to register with kport 13, and

for light reductions in .brake pipe pressure v movement of the piston springs 16, and 17 are properly proportioned,

pipe pressure. If the drop in brake pipe pressure iS sueltas to .cause a greater reduction in pressureon the diaphragm 2 and a consequent Wider opening of the valve 5, then the piston 6 will be moved out so that both ports l() and d11 will register' with the ports 12 and 13. r4This causes-a greater flow of fluid from the supply portion to the bra-ke pipe and correspondingly increased suction action of the Venturi tube 14, which to acelerate the action'of the regulating portion, by increasing the ratee'f redueten in pressure on Vthe l l regulating diaphragm 2. This acceleration of the action of the regulating portion is vpartly neutralized, heweven by the aetien of the spring'N, which-.opposes the further outward so that if the exeessive acceleration of the operation of the regulating neet-ien by .the aeten of the Ventur tube is prevented- Having now deseribed my invention, what I claim as nevi7 and desire to secure by Letters Patent, is :me

l, The eembinatien with 'a source ef'luid y:lindern,reesule and Ve brake pipe, of a feed valve device om'prising a supply valve for controlling the supply etti-uid under pressure from .saidsouree to tbe-'brake pipe, al piston ferr operating said valve, aVentnri device disiposed inthe passage through which said supply valve'supplies fluid to the brake pipe, a regulating valve for ventin piston, and a flexible diep ragniy havin a passage connected to the suction of said turi device for operating said regulating valve, said regulatingvalve eontro'llingcom- V-munication `from saidpieton -to said `suction passage. i

2 The combination with a source of fluid nndernressure .and a brake pipe, of a feed valve evice comprising a supply valve for eontrolling l the supply ofilnidiunder pressure from said source to theAbrake-pipe, a piston for opera-ting said valve,l;a`. spring for opposing Vmovement of said piston, ya second Huid from said spring operative upon a predetermined mOvesaid piston for Iopposing further men-t of vmovement ofsaid pistoma'Venturi device dis- WILLIAM n DEAN. 

